Insulin-like growth factors 1 and 2 (IGF-1 and IGF-2, respectively) promote the differentiation and proliferation of a wide variety of mammalian cell types.
IGF-1 and IGF-2 both circulate widely throughout the body in plasma. They exert their effects on cells by binding to and activating the IGF-1 receptor (IGF-1R). IGF-1R is a member of the family of tyrosine kinase growth factor receptors. Its amino acid sequence is about 70% identical to that of the insulin receptor.
Abnormal IGF-1, IGF-2, and/or IGF-1R activities are associated with a number of medical conditions, including various types of cancer, growth defects (e.g., acromegaly, gigantism, and small stature), psoriasis, atherosclerosis, post angioplasty smooth muscle restonsis of blood vessels, diabetes, microvasular proliferation, neuropathy, loss of muscle mass, and osteoporosis.